This application incorporates by reference the following U.S. patent applications: Ser. No. 09/156,318, filed Sep. 18, 1998; and Ser. No. 09/349,733, filed Jul. 8, 1999.
This application also incorporates by reference the following PCT patent applications: Ser. No. PCT/US98/23095, filed Oct. 30, 1998; Ser. No. PCT/US99/01656, filed Jan. 25, 1999; Ser. No. PCT/US99/03678, filed Feb. 19, 1999; Ser. No. PCT/US99/08410, filed Apr. 16, 1999; and Ser. No. PCT/US99/16057, filed Jul. 15, 1999.
This application also incorporates by reference the following U.S. provisional patent applications: Ser. No. 60/094,275, filed Jul. 27, 1998; Ser. No.60/094,276, filed Jul. 27, 1998; Ser. No.60/094,306, filed Jul. 27, 1998; Ser. No. 60/100,817, filed Sep. 18, 1998; Ser. No. 60/100,951, filed Sep. 18, 1998; Ser. No. 60/104,964, filed Oct. 20, 1998; Ser. No. 60/114,209, filed Dec. 29 , 1998 ; Ser. No. 60/116,113, filed Jan. 15, 1999; Ser. No. 60/117,278, filed Jan. 26, 1999; Ser. No. 60/119,884, filed Feb. 12, 1999; Ser. No. 60/121,229, filed Feb. 23, 1999; Ser. No. 60/124,686, filed Mar. 16, 1999; Ser. No. 60/125,346, filed Mar. 19, 1999; Ser. No. 60/126,661, filed Mar. 29, 1999; Ser. No. 60/130,149, filed Apr. 20, 1999; Ser. No. 60/132,262, filed May 3, 1999; Ser. No. 60/132,263, filed May 3, 1999; Ser. No. 60/135,284, filed May 21, 1999; Ser. No. 60/136,566, filed May 28, 1999; Ser. No. 60/138,311, filed Jun. 9, 1999; Ser. No. 60/138,438, filed Jun. 10, 1999; Ser. No. 60/138,737, filed Jun. 11, 1999; Ser. No. 60/138,893, filed Jun. 11, 1999; and Ser. No. 60/142,721, filed Jul. 7, 1999.
This application also incorporates by reference the following publications: Max Born and Emil Wolf, Principles of Optics (6th ed. 1980); Richard P. Haugland, Handbook of Fluorescent Probes and Research Chemicals (6th ed. 1996); and Joseph R. Lakowicz, Principles of Fluorescence Spectroscopy (1983).
The invention relates to techniques for analyzing samples. More particularly, the invention relates to devices and methods for containing and optically analyzing small sample volumes.
The proliferation of biological targets and candidate drug compounds in high-throughput screening and the increased interest in characterizing the human genome have created a significant need for rapid, efficient, and reproducible analysis of many samples. Moreover, there often is a significant need to perform assays in high-throughput screening, genomics, and other applications, with minimal sample volumes that conserve potentially precious or costly reagents without sacrificing sensitivity and reproducibility.
Microscopists in particular have developed procedures for handling small sample volumes. A common format for microscopically analyzing biological samples is to sandwich the sample between parallel surfaces, such as opposing surfaces on a glass slide and coverslip. Unfortunately, microscope slides have significant limitations, particularly for performing quantitative assays in a reproducible high-throughput testing mode. First, microscope slides are usually assembled manually, which typically is slow and subject to operator variability or error, such as bubble formation. Second, the thickness of a sample sandwiched between surfaces of a microscope slide and coverslip can vary with sample volume, because the sample tends to spread between the surfaces until it reaches the edges of the smaller of the surfaces. Variations in sample thickness can cause variations in results, depending on the assay. Third, microscope slides often leave samples at least partially exposed to the ambient environment, which can cause analyte concentrations to vary if evaporation occurs. Variations in analyte concentration can kill cells and perturb binding rates and coefficients.
The invention provides devices and methods for containing and analyzing small sample volumes that are sandwiched between solid surfaces. The devices may include an automated drive mechanism that controls the relative positions of the surfaces and an environmental-control mechanism that controls the humidity, temperature, and/or other environmental conditions around the small sample volume. In some embodiments, at least one of the surfaces has a light-transmissive window for allowing optical analysis of a sample contained between the surfaces.